Prior to the present invention, it has been known to react formaldehyde with acetone to obtain methyl vinyl ketone and with various other See Ember U.S. Pat. No. 3,928,457.
A general reaction for the preparation of an alpha, beta unsaturated ketone by catalytic vapor phase condensation of formaldehyde and a ketone is disclosed in U.S. Pat. No. 3,928,458.
In Mottern U.S. Pat. No. 2,549,508, Example V, methyl ethyl ketone is reacted in the vapor phase with formaldehyde in the presence of a solid mixture of zinc oxide and zirconium oxide to form methyl isopropenyl ketone.
The literature also teaches the separate use of secondary amines and strong acid or weak acid salts of secondary amines for the reaction of ketones and, primarily, aldehydes, with aqueous formaldehyde (monomeric) to form the corresponding vinyl aldehyde and ketones (see Ai, M. J., Catal., 1987, 106, 2734; Ueda, W. Yokoyama, T., Moro-Oka, Y., Ikawa, T., J. Chem. Soc., Chem. Commun., 1984, 39 ; Gutsche, D. C., Nam., K.C., J. Am. Chem. Soc., 1988, 110, 6153; U.S. Pat. Nos. 4,275,242, 4,343,239, 4,406,079 and 4,496,770). A tertiary amine is used in U.S. Pat. No. 3,077,500.
The reader may also be interested in reviewing U.S. Pat. Nos. 3,928,450 and 3,701,798. The '798 patent uses an oxide of a rare earth metal as a catalyst.
In Heinz et al U.S. Pat. No. 3,077,500, methyl ethyl ketone is reacted with aqueous formaldehyde in the presence of a tertiary amine with and without anion exchange resin catalysts. However, methyl isopropenyl ketone is obtained only by dehydrogenating the reaction product.
U.S. Pat. No. 3,422,148 also discloses a method of making methyl isopropenyl ketone. In this process, methyl ethyl ketone is reacted with aqueous formaldehyde in the presence of an "acidic cation exchange resin." No paraformaldehyde is mentioned; applicants' catalyst is different.
The use of paraformaldehyde in the manufacture of certain saturated carbonyl-containing compounds is suggested in U.S. Pat. No. 4,374,274. The process further differs from that disclosed herein in that it employs a palladium catalyst deposited on a particular phosphate base.